The direct reduction of iron oxide to metallic iron has become a worldwide reality, and direct reduced iron is a commercially accepted feed material in iron and steelmaking.
Direct reduced iron, or sponge iron, is particularly well suited for electric arc furnace technology. It is not suitable as the principal feed material for other steelmaking furnaces, such as the bottom blown oxygen process, which require hot metal or molten metal, as feed material. At present, such hot metal is produced commercially only by means of blast furnaces which are inherently tied to the availability of coking coal and to integrated steelmaking installations. It is, therefore, desirable to produce molten iron by direct reduction means which are economically suitable for small steelmaking installations and are independent of the use of coking coal.
The present invention accomplishes this end by (1) producing hot direct reduced iron (DRI) from particulate iron oxide in an efficient counterflow shaft furnace, (2) discharging the hot DRI into a molten bath of iron in a melter-gasifier chamber, (3) impinging coal and oxygen onto the molten bath to supply heat to melt the hot DRI and gasify the coal, and (4) passing off the gases from the melter-gasifier through the shaft furnace to reduce the iron oxide. The process is simple, efficient, nonpolluting, economical for small steelmaking installations, and suitable for use with noncoking coals which are available worldwide.